ethtool: plca: fix plca enable data type while parsing the value

The ETHTOOL_A_PLCA_ENABLED data type is u8. But while parsing the
value from the attribute, nla_get_u32() is used in the plca_update_sint()
function instead of nla_get_u8(). So plca_cfg.enabled variable is updated
with some garbage value instead of 0 or 1 and always enables plca even
though plca is disabled through ethtool application. This bug has been
fixed by parsing the values based on the attributes type in the policy.

Fixes: 8580e16c ("net/ethtool: add netlink interface for the PLCA RS")
Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20230908044548.5878-1-Parthiban.Veerasooran@microchip.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ethtool/plca.c

@@ -21,16 +21,6 @@ struct plca_reply_data {
 #define PLCA_REPDATA(__reply_base) \
 	container_of(__reply_base, struct plca_reply_data, base)
 
-static void plca_update_sint(int *dst, const struct nlattr *attr,
-			     bool *mod)
-{
-	if (!attr)
-		return;
-
-	*dst = nla_get_u32(attr);
-	*mod = true;
-}
-
 // PLCA get configuration message ------------------------------------------- //
 
 const struct nla_policy ethnl_plca_get_cfg_policy[] = {
@@ -38,6 +28,29 @@ const struct nla_policy ethnl_plca_get_cfg_policy[] = {
 		NLA_POLICY_NESTED(ethnl_header_policy),
 };
 
+static void plca_update_sint(int *dst, struct nlattr **tb, u32 attrid,
+			     bool *mod)
+{
+	const struct nlattr *attr = tb[attrid];
+
+	if (!attr ||
+	    WARN_ON_ONCE(attrid >= ARRAY_SIZE(ethnl_plca_set_cfg_policy)))
+		return;
+
+	switch (ethnl_plca_set_cfg_policy[attrid].type) {
+	case NLA_U8:
+		*dst = nla_get_u8(attr);
+		break;
+	case NLA_U32:
+		*dst = nla_get_u32(attr);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+	}
+
+	*mod = true;
+}
+
 static int plca_get_cfg_prepare_data(const struct ethnl_req_info *req_base,
 				     struct ethnl_reply_data *reply_base,
 				     const struct genl_info *info)
@@ -144,13 +157,13 @@ ethnl_set_plca(struct ethnl_req_info *req_info, struct genl_info *info)
 		return -EOPNOTSUPP;
 
 	memset(&plca_cfg, 0xff, sizeof(plca_cfg));
-	plca_update_sint(&plca_cfg.enabled, tb[ETHTOOL_A_PLCA_ENABLED], &mod);
-	plca_update_sint(&plca_cfg.node_id, tb[ETHTOOL_A_PLCA_NODE_ID], &mod);
-	plca_update_sint(&plca_cfg.node_cnt, tb[ETHTOOL_A_PLCA_NODE_CNT], &mod);
-	plca_update_sint(&plca_cfg.to_tmr, tb[ETHTOOL_A_PLCA_TO_TMR], &mod);
-	plca_update_sint(&plca_cfg.burst_cnt, tb[ETHTOOL_A_PLCA_BURST_CNT],
+	plca_update_sint(&plca_cfg.enabled, tb, ETHTOOL_A_PLCA_ENABLED, &mod);
+	plca_update_sint(&plca_cfg.node_id, tb, ETHTOOL_A_PLCA_NODE_ID, &mod);
+	plca_update_sint(&plca_cfg.node_cnt, tb, ETHTOOL_A_PLCA_NODE_CNT, &mod);
+	plca_update_sint(&plca_cfg.to_tmr, tb, ETHTOOL_A_PLCA_TO_TMR, &mod);
+	plca_update_sint(&plca_cfg.burst_cnt, tb, ETHTOOL_A_PLCA_BURST_CNT,
 			 &mod);
-	plca_update_sint(&plca_cfg.burst_tmr, tb[ETHTOOL_A_PLCA_BURST_TMR],
+	plca_update_sint(&plca_cfg.burst_tmr, tb, ETHTOOL_A_PLCA_BURST_TMR,
 			 &mod);
 	if (!mod)
 		return 0;